Furnace



R. MARK FURNACE.

APPLICATION FILED, MAY 6. r920.

Patented Dem fl W21 4 $HEETSSHEET l- R. MARX.

FURNACE.

APPLlCATlON FILED MAY 6,1920.

1,399,638, Patentedl Dec. 6,, 1921.,

4 SHEETSSHEET 2.

R. MARX.

FURNACE.

APPLICATION FILED MAY 6, I920.

'JPatented Dec 6, 1921.

4 SHEETSSHEET 3.

R, MARX.

FURNACE. APPLICATION FILED MAY 6, 1920- Pa'tentm Deco 7 6,, 1921.,

4 SHEETSSHEET 4.

UNITED STATES RICHARD MARX, O-F PHILADELPHIA, PENNSYLVANIA.

FURNACE. 1

Specification of Letters Patent.

Patented Dec. 6., 1921.

Application filedMay 6, 1920. Serial No. 379,320.

To all whom it may concern:

Be it known that I, RICHARD MARX, a citizen of the United States,residing in Philadelphia, Pennsylvania, have invented Furnaces, of whichthe following is a specification. I

One object of this invention is to provide a furnace of the general typedescribed and claimed in my application for U. S. Patent #328,442, filedOctober 4, 1919, whose construction shall besuch that a part of itsfloor within its oxygen free heating chamber may be kept relatlvelycool, inorder to permit-of the heat treatment of but a portion of anobject such as a die cutter or some other tool placed on the furnace.

A further object of the invention is to provide a novel form of heatingfurnace which shall permit of the use of a bath of some liquid inpermanent communication with its oxygen free chamber, either with a vlewto maintaining the liquid itself in a fused condition without subjectingit to the oxidizing action-of the air, or of making possible thetransfer of articles from the interior of the furnace to the liquidWithout subjecting them to material cooling or oxidation.

These objects and other advantageous ends I attain as hereinafter setforth, reference being had to the accompanying drawlugs, in which,

Figure 1 1s a side elevation of a furnace embodying my invention;

Fig. 2 1s a transverse section on the line 2-2, Fig; 1; i

Fig. 3 isa sectionon the line.3--3', Fig. 2;

Fig. li-is a horizontal section on the line an, Fig. 1;

Fig-,5 is a front elevation of a modification of my invention;

Fig, 6 is, a vertical section on the line 6--6,

5; 1 lg. 77 is, a side elevation of another form of the invention;

Fi 8. is a vertical section on the line 8--8, Fi a and 1g. '9 is afragmentary vertical section on the line 9-9, Fig. 7.

Tn the above drawings 1 represents the metal inclosing casing of amuffle furnace which is usually supported on a set of legs 2 and has arefractory lining 3. In the interior of this structure is mounted amuffle consisting in the present instance of an elongated metal chamber4 open only at the floor, sides, top and back of the furnace chamber andis permanently open through the front of the casing 1, although thecombustion space 6 surrounding it is cut off from this front opening.Said space how- 'ever is provided at its top with suitable outlets 7 forthe escape of products of combustion and is designed to be heated bysome form of gaseous fuel delivered from two sets of burners 8discharging into its lower portion from opposite sides.

These burners through pipes 9 and 10 are supplied with a mixture of airand gas from mains 11 and 12 and the proportions of these ingredientsmay be regulated by valves 13 and 14 connected between the mains and thepipe 10. Extending transversely below the level of the floor of themuffle immediately adjacent its open end is a burner in the form of apipe 15 having a series of closely spaced relatively small openingsformed along its topmost portion designed to supply a series of jets offuel all in the same substantially vertical plane at orimmediatelyadjacent the entrance to the muffle 41. The fuel for thesejets is delivered through a pipe 16 supplied from the mains 11 and 12and regulated as to its composition by a pair of valves 17 and 18. Uponbeing ignited the fuel escaping from th1s burner forms a continuoussheet or our tain of burning fuel which completely closes the opening tothe muffle and prevents entrance ofair thereto as'well as extractsoxygenfrom its interior.v

The bottom of the muffle 4:, in the present instance immediatelyadjacent the front thereof, has an outlet opening 19 to which isconnected a vertical conduit 20 whose lower end opens below the surfaceof a liquid such as oil within a "container 21 placedunder the furnace.A shelf 22 is fixed to the front of'the furnace casing so that its topsurface is continuous with said muffle floor and serves to supportarticles burners 8 into the space 6', and oxygen is not only excludedbut is removedfrom the interior of said muffle by the curtain of burningfuel indicated at w in Fig. 1, which is delivered across its open endfrom the burner pipe 15. After said latter burner has been in operationfor a relatively short period only inert gases such as nitrogen andcarbon dioxid remain within the mufi'le so that articles to be subjectedto a heat treatment may be introduced through said curtain and raised tothe desired temperature without being subjected to the objectionableposed to the atmosphere.

If it be desired to raise but a portion of any given object such as adie or cutter to a high temperature under the conditions abovedescribed, I may construct the furnace as shown in Figs. 7 to 9inclusive, in which an airflue or passage 25 is provided under the metalfloor or bottom of the muffle at some distance to the rear of the burner15 for formlng the oxygen excluding curtain.

This conduit has an lnlet opening 26 preferably at its middle portion sothat a current of cool air may enter at this point and divide so as toflow in opposite directions under the front portion of the bottom of themuffle and be discharged through outlets 27 in the side of the furnacecasing. Obviously that portion of the floor. of the mufiie between thepassage or conduit 25 and the burner pipe 15 is maintained by this airflow at a relatively low temperature, while the remainder of the mufileis raised to and kept at a uniform high temperature by the burning fueldelivered from the burners 8;-it being understood that the conduit.25,is preferably formed in refractory material under 'the floor of themuflie. Obviously a metal structure such as a die or tool resting on thefront part of the mufilefloor would have that portion to the rear of theconduit 25 highly heated while its portion in.front of saidconduit'would be kept relatively cool by conduction of its heat .pipe 15extending across the floor of the mufiie so as to discharge a curtain ofburn- -ing fuel across its second open. end as indi-' cated at 00 .Withthis construction material may be introduced to and removed from themuffle through either end thereof.

When a molten metal such as lead-isto to the cool part of the be used asa quenching material rather than oil, I may construct the furnace asshown in Figs. 5 and 6 in which form of my invention I provide a hollowmetal casing 30 in the form of. abox having an inwardly extendin flange31 around its open upper edges. This flange is designed to receive acasing in the form of a metal pot 32 suspended within the body of thebox-like casing 30 and extended upwardly in the form of a cover or hood33 having an opening in its forward side. As illustrated the structure32-33 is a casting having a perforated conduit 34 extending through itin position to discharge aseous fuel in the form of a sheet upward yacross the opening into its top 33. This passage or channel is connectedto a source of fuel through a pipe 35 and a burner 36 is provided underthe pot,32 within the casing 30 so that a body of lead 37 for examplemay be fused and maintained in a molten condition. Oxidation of thislead is prevented by the curtain 00 of burning fuel supplied from theconduit 34 across the opening-into the top'33 so that articles to bequenched may be introduced through said curtain and plunged I into ormaintained in the lead in the pot 32 without being exposed to the oxygenin the atmosphere after having passed through said curtain. Obviouslythe lead may be maintained indefinitely in a melted condition withoutoxidation as long as the curtain :r'- is provided, it being understoodthat in this as well as in the other forms of my invention the air andgas supplying said curtain are -so proportioned that as the fuel isburned the oxygen is removed from the interior of the mulile or otherheating chamber.

1, claim 1. The combination in a furnace of a inuflie having an opening;means for heating said muffle; means for maintaining a curtain ofburning gaseous material across said opening; and means for causing aportion of the bottom of the muliie to be cooler than the remainder.

' 2. The combination in a furnace of a .muflle havingan air passageconnected to the atmosphere and extending under a portion of its floor;means for heating. said mufiie; and means for preventing access ofoxygen to the muflie consisting of a device for delivering a burninggaseous curtain across the opening of the mufiie.

3. The combination in a furnace of a casing having, a heating chamber;means for mounted in said chamber; means for permitting,circulation.ofair under a portion ofthe floor of said mufiie to maintain the same at arelatively low temperature; and means for excluding oxygen from themuflie consisting of a burner tube positioned to supply a supplying fuelto said chamber; a mu-fiie the floor thereof which is maintained at alow temperature.

4. The combination in a furnace of a mufiie having an opening; means formaintaining a curtain of burning fuel across said opening to excludeoxygen from the muffle; and a liquid container communicating with themufile.

5. The combination of a furnace having a muflie provided with an inletopening and having an opening in its floor; means for supplying acurtain of burning fuel across said inlet opening; and a container cutoil from the atmosphere and communicating With said mufile through theopening in its floor.

6. The combination of a furnace having a mu'lile provided with adelivery opening and an inlet opening; a container having a body ofliquid therein; a conduit leading from the delivery opening of themuffle to a point below the surface of the liquid in the container; andmeans for forming an air exeluding curtain across the inlet opening ofthe muflle.

7. The combination of a casing having an opening; a container for liquidcommunicating with said casing; and a burner for supplying a curtainopening.

8. The combination in a furnace of an inclosing casingra refractorylining forming a heating chamber; a muflie mounted in said chamber andhaving an opening to the atmosphere; means for providing a curtain ofgaseous fuel across said opening consisting of a burner tube extendingadjacent the opening; and means for forming an air conduit under thefloor of the muffle to the rear of said opening.

of gaseous fuel across the RICHARD MARX.

